Hot-air engine



(No Model.)

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J. J. MQTIGHE.

HOT AIR ENGINE.

Patented Jul 7, 1885..

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(No Model.) I 3 Sheets-Sheet 2. J. J. MGTIGHB.

7 HOT AIR ENGINE. No. 321,739. Patented July 7, 1885 i I ,f 5 J am mu,muvmu mwmmn c (No Model.) 1 3 Sheetsr-Sheet 3. J. 'J. McTIGHE.

HOT AIR ENGINE.

I ZNVENTOR l A TTORNE, 1g

UNITED STATES PATENT JAMES J. MCTIGHE, OF FREEPOR'I, PENNSYLVANIA.

HOT-AIR ENGINE.

SPECIFICATION forming part of Letters Patent No.321,739, dated July 7,1885.

Application filed January 28, 1885.

To aZZ whom it may concern.-

Be it known that 1, JAMES J. MOTIGHE, of Freeport, in the county ofArmstrong and State of Pennsylvania, have invented certain new anduseful Improvementsin Hot-Air Engines; and I do hereby declare that thefollowing is a full, clear, and exact description of the invention,which will enable others skilled in the art to which it appertains tomake and use the same, reference being had to the accompanying drawings,which form a part of this specification, in which- Figurel is ahorizontal sectional view; Fig. 2, a top view. Fig. 3 is a verticalsection of heating-tube. Fig. 4 is a vertical side view, partly insection. Fig. 5 is a vertical section of lower part of heating andcooling chamber, showing connecting pipe. Fig. 6 isa vertical sectionalView of working-cylinder and pistons. Fig. 7 is a view showing stove orheater and method of connecting flue with both sides of heating-tubes.

This invention has relation to that class of hot-air engines in whichthe same air, whether previously compressed or not, is used over andover again, and has for its object to provide an engine very compact insize, economical. and reliable in its working, and of such power as tobecome a substitute, in many cases, where only steam can now be'used.

My invention consists, first, in the nove form of heating and cooling orreversing chambers; secondly, in the novel arrangement of heating andcooling devices within said chambers; thirdly, in the novel form ofreversing mechanism contained within said chambers; fourthly, in thenovel arrangement of the working'cylinders; fifthly, in the novel meansfor utilizing superfluous expansive power; sixthly, in the novel means.for preventing heating or cooling of the air at times not needed;seventhly, in all the arrangements and combination of parts hereinafterfully described, and more fully claimed.

In Fig. 1, A represents a hollow cylinder closed at both ends by caps,one of which is removable. This cylinder is divided into two parts orchambers, A A, by the wall B, each portion being made air-tight both asregards communication with the external atmosphere and with each other.The chambers A A (No model.)

are again divided into two portions by the semicircular partitions a a,which are fastened to the walls of the cylinder by screws, and, beingslotted, are free to move under the expanding force of the heat to whichthey will be submitted. The parts between'the parlitions and the sidesof the cylinders are fillcd with loose iron plates, forming theregenerators.

The four corners of the chambers formed by the junction of thedividing-wall B and the periphery of the cylinder are partly occupied bytubes 0 O G O, of which a detailed description will be given further on.For the present, suffice it to say that the tubes 0 C in the right-handcorners of Fig. 1 are cool ing-tubes, containing circulating water, andthe tubes 0 O in the left-hand corners contain passing flame andconstitute the heating devices of the engine. A certain portion of thebalance of the chambersis taken up with the reversers D D, which, asappears, are, in a plan view, somewhat of a shield form, and oscillateor rock on their axes. These revels ers always occupy positions asnearly diametrically opposite as possible, the result being that whilethe air in one chamber is being heated that in the other is beingcooled. Obviousl y, as these reversers oscillate they change the airfrom the hot corner to the cool, and vice versa, in each chamber,respectively.

The object of shaping the reversers as shown in Fig. 1 is that there maybe as little useless air-space as possible in the side or corner wherethe air is not wanted. Near the ends of the semicircular partitions a aare placed gates or clack-valves (Z d, so arranged as to close when theair is following and to open when it is preceding the reverser. Thepurpose of this is to draw the air around and through the heating orcooling devices when it is desired to heat or cool it, and to furnish itwith a shunt passage away from said devices when the aim is to avoid theheating or cooling. The gates or valves (1 d, as shown in the drawings,being clack-valves, are automatic in their working, but may be of suchconstruction as to be actuated, when required, by a posi tive motionfrom the engine-shaft, the means for so doing being very obvious.

The reversers are of course operated by a positive motion from theshaft, somewhat in a similar manner and in nearly the same relativetimes as the valves of a steam-engine. To the upper end of the reversersare attached shafts which pass out through and are packed in the top orcover of the cylinder. These twin shafts may be made to turnsimultaneously and in any desired periods by many different means. Oneway is shown in the drawiugsviz., to fasten to each shaft above'the topof the cylinder a small gear-wheel, it, another cog-wheel, k, meshinginto and pivoted between them. By turning the central wheel the othertwo turn in opposite directions, and the reversers within the chambersare compelled to follow and preserve their diametric relations. As shownin Figs. 2 and 6, the central wheel is made to oscillate by the use oflevers and a cam on the engine-shaft; but any other suitable means maybeadopted. The aim being to cause the reversers to rock to and fro abouttheir respective axes, this purpose -an be obtained in various wayswithout addinganything to this invention. The reversers are shown inFig. 1 in section; but it is to be understood that they are also cappedand airtight. They may also be divided into compartments, the end towardthe cold side of each chamber containing circulating water let inthrough the shafts and making its exit by the same, as is commonlyprovided in similar circumstances in ice-making machines.

The two chambers of the reversing-cylinder communicate, respectively, bythe open passages E E, Fig. 1, with the two singleaetingworking-eylindersthat is, chamber E to the clearance-space above thepiston in cylinder F, and chamber E to the clearance space above thepiston in cylinder F. These working cylinders containtrunk-pistons ff ofany desired pattern, and their connecting-rods actuate the cranks r g ofthe main shalt G,together with its various attachments, as in anyordinary steanrengine. These twin working cylinders are placed mouthdownward for a twofold purpose first, to prevent oil or water gettinginto the reverser-cylinders,where under the influence of great heatdamage might result to the engine; and, secondly, to prevent as far aspossible the oil used in lubricating getting behind or rather above thepistons, where, owing to its gradually becoming gummy,it would increasethe friction. In steam-engines this oil would be blown out through theexhaust; but as there is no exhaust in this class of hot-air enginesmeans must be adopted to prevent the above inconveniences, and the bestway is to place the mouths of the workingcylinder downward. A box orother vessel may be attached to the mouths of these working-cylindersfor oil and water for the purpose of better lubrication and to preventwaste of oil. This method of and means for lubricating theworking-cylinders is well known, but has never heretofore been appliedto a hot-air engine,and in this regard may be considered not merelyadvantageous,

but really necessary. The two chambers of the reversing cylinder areconnected by a pipe, H, Fig. 5. This pipe is closed normally by aplug-valve, which may be opened at any desired moment by a cam on theengine-shaft and immediately reclosed. This valve is pref erably anoscillating one,and its aim is to establish a brief communicationbetween the two reversing chambers,as will appear further 011.

The four tubes 0 C (J C, Fig. 1, above re ferred to, are constructedsubstantially as shown in Fig. 3. As seen, none of the tubes are quiteequal to the internal length of the reversing-eylinder, and each one isdivided into two compartments by a wall, c,which goes near to the closedend of the tubes, thus leaving a communicating space, 71, between thecompartments. This wall is perforated to es tablish a communicationacross or through the tube, through which the air in thereverser-cylinders may pass, as before men tioned. In one case the heator flame goes up one side of the tube from the grate, stove, or burner,and down the other side to the flue. In the other case the water followsa like course from the faucet to the waste. Thus high and lowtemperatures are maintained, as desired, and entirely within therevel-senchambers,and very extensive heating and cooling surfacesprovided.

The heating-tubes may and must be arranged in any convenient manner toallow for expansion, and when cast separately from the cylindcrs may bereadily replaced when burned out.

A small air-pump operated by the motion of the engine-shaft communicateswith a reservoir provided with two exit-pipes, each communieating withone of the reverser-chambers, and each having a check-valve to preventthe return of air to the reservoir. The rcservoi r itself has anordinary safety-valve,whie11 may be loaded to any desired pressure.Whatever that pressure be will be theoretically the work ing pressure ofthe engine, as will appear further on. Thus it will be possible todetermine and set the horse-power desired in any degree or fractionwithin thelimits of bursting pressure of the various parts of theengine.

The operation of the engine is as follows: The reverser-chambers A A andtheir respective communicating working-cylimlers F F are first chargedby hand or otherwise with air at any desired pressure. It may be theatmospheric pressureflifteen pounds, which needs no charging; butsuppose they be charged to sixty pounds. The flame and water are letintotheir respective tubes, and let the heatingtubes be heated to about500 Fahrenheit, the cool-tubes remaining, say, at In this circumstancethe heated air acquires a tension of about one hundred and twentypounds, while the cold air in the other chamber remains at sixty poundstension. Evidently the piston connecting to the chamber containingheated air will commence to descend undcrthe difference of tension ofthetwo chambersviz.,120

IIO

pressed.

60:60 pounds. At the same time the other piston is being forced upward,compressing the air ahead of it. This compression produces a cer tainamount of heat, which is being rapidly extracted by the water of thetube in its cool-' ing-chamber and into which it is being com- Theseare-truths long since demonstrated by Stirling and others, and are onlyreferred to in order to explain completely the working of the presentinvention. The piston under tension or pressure of heated and expandingair, retaining yet the tension practt cally of one hundred and twentypounds, is about to complete its stroke, the other piston likewise beingabout on the point of finishing its stroke and consequent compression ofcold and cooling air at substantially sixty pounds pressure. At thisprecise juncture, if the valve between the two reversing-chambers besuddenly opened, as it will be by the revolution of the engine-shaft,the tension between the two chambers becomes at once balanced, onefalling from one hundred and twenty pounds to ninety pounds and theother rising to ninety pounds from sixty pounds. Here is a dead point.The movement of the fly-wheel carries itself beyond the dead-point. Thevalve above referred to is closed by a positive motion. By a positivemotion, also, the reversers are immediately changed and the shaftreceives a new impulse from the tension of the air heating in the secondchamber and cooling in'the first. Thus the operation proceeds. In themeantime the pump is being also operated, the reservoirsafety-valvebeing loaded, say, to sixty pounds. If at any time the airin either reversing-chamber, owing to leakage, becomes less than sixtypounds, sufficient air will pass to it from the reservoir to restore itto -its normal pressure when cold.

Thus the engine will work at any pressure which the material of which itis constructed will withstand. Its working pressure will betheoretically the difference of pressure between the tworeservoir-chambersin practice lessor, in other words, its theoreticalworking pressure will be the load carried on the safety-valve of thereservoir.

- Having described myinvontion, I claim 1. A reverser-chamber forhot-air engines, divided into compartments, each compartment having avibrating reverser, substantially as shown and described.

2. A reverserchamber for hot-air engines, divided into compartments,each compartment having a vibrating reverser therein, and aworkingcylinder communicating therewith, substantially as described.

3. A reversing device for hot-air engines, consisting of chambers, and ameans, substan tially as shown and described, for establishingcommunication between said chambers, whereby the superfluous pressure atthe end of the stroke of the piston is transferred from one chamber tothe other.

4. In a hot-air engine, the combination of a vibrating or rockingreverser and a heating or cooling device contained within the samechamber, substantially as described.

5. In a hotair engine, the combination of a heater and cooler and avibrating or rocking reverser contained within said chamber,substantially as described.

6. In a hot-air engine, the combination of chamber A, inclosing heatingor cooling tubes 0 O, with vibrating reverser D, whereby the air istransferred from one side of the chamber to the other, substantially asdescribed.

7. In a reverser for hot-air engines, the combination of heating andcooling devices with shunt or auxiliary passages connecting the ends ofsaid reversing-chambers, substantially as described, whereby the air maybe trans ferred from one end to the other without com ing in contactwith the heating or cooling devices.

In testimony that I claim the foregoing as my own I have hereto affixedmy signature in presence of two witnesses.

JAMES J BIOTIGHE.

WVitnesscs:

A- A. Moonn, THOS. A. CoNNoLLY.

